RESUMO
Icariside II (ICAII) is a bioflavonoid compound which has demonstrated antioxidative, antiinflammatory and antiapoptotic biological activities. However, to the best of our knowledge, whether ICAII can alleviate myocardial ischemia and reperfusion injury (MIRI) remains unknown. The aim of the present study was to determine whether ICAII exerted a protective effect on MIRI and to investigate the potential underlying mechanism of action. A rat MIRI model was established by ligation of the left anterior descending coronary artery for 30 min, followed by a 24 h reperfusion. Pretreatment with ICAII with or without a PI3K/AKT inhibitor was administered at the beginning of reperfusion. Morphological and histological analyses were detected using hematoxylin and eosin staining; the infarct size was measured using Evans blue and 2,3,5triphenyltetrazolium chloride staining; and plasma levels of lactate dehydrogenase (LDH) and creatine kinasemyocardial band (CKMB) were analyzed using commercialized assay kits. In addition, the cardiac function was evaluated by echocardiography and the levels of cardiomyocyte apoptosis were determined using a TUNEL staining. The protein expression levels of Bax, Bcl2, cleaved caspase3, interleukin6, tumor necrosis factorα, PI3K, phosphorylated (p)PI3K, AKT and pAKT were analyzed using western blotting analysis. ICAII significantly reduced the infarct size, decreased the release of LDH and CKMB and improved the cardiac function induced by IR injury. Moreover, ICAII pretreatment significantly inhibited myocardial apoptosis and the inflammatory response. ICAII also upregulated the expression levels of pPI3K and pAKT. However, the protective effects of ICAII were abolished by an inhibitor (LY294002) of the PI3K/AKT signaling pathway. In conclusion, the findings of the present study suggested that ICAII may mitigate MIRI by activating the PI3K/AKT signaling pathway.